Variable-capacity vane pump

ABSTRACT

A pump is provided, which includes: an internal housing inside which a vane rotor is housed; a pump housing  1  in which the centre of rotation of the vane rotor is immovable and the internal housing is able to move; a first control oil chamber which causes the internal housing to move in a direction of decreasing the discharge volume; and a second control oil chamber which causes the internal housing to move in a direction of increasing the discharge volume; a pressure adjustment valve; a temperature-sensitive valve; and an elastic member which elastically impels the internal housing. A flow passage area of the temperature-sensitive valve changes gradually with change in oil temperature, and the pressure adjustment valve changes a discharge volume in accordance with increase in pressure of the discharge oil.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a variable-capacity vane pump which can set suitable oil discharge volumes in accordance with respective rotational speeds, and which can have an extremely simple structure for this purpose.

2. Description of the Related Art

Conventionally, there are various types of vane pump which are capable of changing the discharge volume. Japanese Patent Application Publication No. 2015-021400 discloses a typical example of this. Japanese Patent Application Publication No. 2015-021400 discloses a variable-capacity pump which is capable of changing the discharge volume of the pump by swinging movement of a cam ring (5). In the embodiments of Japanese Patent Application Publication No. 2015-021400, a discharge port (12), a temperature-sensitive valve (6) which opens and closes with expansion or contraction of a wax pellet (41), a pilot valve (7), to the downstream side thereof, which opens and closes with the oil pressure, and a second control oil chamber (17), to the downstream side thereof.

SUMMARY OF THE INVENTION

The cam ring (5) is made to perform a swinging action by applying, or not applying an oil pressure to a second control oil chamber (17). The configuration of Japanese Patent Application Publication No. 2015-021400 involves the following problems. Firstly, two springs, a first coil spring (27) and a second coil spring (28) are used, which means an increase in the number of components and the required installation space. Furthermore, since the second control oil chamber (17) is arranged sequentially, in series on the downstream side of the pilot valve (7) which opens and closes in accordance with the oil pressure and which is arranged sequentially on the downstream side of the temperature-sensitive valve (6) which opens and closes in accordance with the oil temperature, then the element that actually regulates the oil pressure in the second control oil chamber (17) is the pilot valve (7).

An oil passage (36) and a supply and discharge passage (37) only communicate with each other when the spool valve (52) of the pilot valve (7) is in a certain specific position in the axial direction, and in this case only, the temperature-sensitive valve (6) and the second control oil chamber (17) are communicated and oil pressure from the temperature-sensitive valve (6) is transmitted to the second control oil chamber (17). If the temperature-sensitive valve (6) and the second control oil chamber (17) are not communicated with each other, then the oil pressure is controlled by the pilot valve (7) only, and it is difficult to raise the freedom of the control range.

Furthermore, the pilot valve (7) only has two control modes, which are either to apply oil pressure or to release oil pressure, to/from the second control oil chamber (17) via the supply/discharge passage (37). Therefore, it is difficult to raise the freedom of the control range. Furthermore, an upstream end (35a) of a communication passage (35) and a drain port (54), the oil passage (36) and the second drain port (56), and an open end (35b) of the communication passage (35) and a first drain port (59), are all in a non-communicated state at all rotational speeds.

The oil discharged from the discharge port (12) of the pump is not discharged (relieved) from anywhere, but rather is supplied entirely to the control oil chambers (16, 17) or to a main oil gallery (13) (engine). Therefore, if a relief valve is to be provided in this configuration in order to suppress increase in the oil pressure in the event of high oil pressure, then it is necessary to provide the relief valve separately from this configuration, thus resulting in increased space and cost requirements.

Therefore, the object of the present invention (the problem to be solved) is to provide a variable-capacity vane pump which is capable of setting suitable oil discharge volumes in accordance with respective rotational speeds, and which has an extremely simple structure for this purposes.

The inventors, as a result of repeated thorough research aimed at resolving the abovementioned problem, resolved the problem by configuring a first embodiment of the present invention to be a variable-capacity vane pump including: a vane rotor configured of a rotor section into which a plurality of vanes are inserted in projectable fashion; an internal housing having a rotor chamber in which the vane rotor is accommodated; a pump housing having an accommodating chamber in which the centre of rotation of the vane rotor is immobile and the internal housing is able to move; a first control oil chamber which moves the internal housing inside the accommodating chamber of the pump housing in a direction of decreasing a discharge volume; a second control oil chamber which moves the internal housing inside the accommodating chamber of the pump housing in a direction of increasing the discharge volume; a pressure adjustment valve which discharges oil inside the second control oil chamber of the pump housing; a temperature-sensitive valve into which a portion of the discharge oil flows; and an elastic member which is provided in the pump housing and which elastically impels the internal housing in a direction of increasing the volume of discharge by the vane rotor, wherein a flow passage area of the temperature-sensitive valve progressively changes as the oil temperature changes, and the pressure adjustment valve changes the discharge volume in accordance with increase in pressure of the discharge oil.

The abovementioned problem was resolved by configuring a second embodiment of the present invention to be the variable-capacity vane pump of the first embodiment, wherein the temperature-sensitive valve has a role of relieving a portion of the discharge oil. The abovementioned problem was also resolved by configuring a third embodiment of the present invention as the variable-capacity vane pump of the first embodiment, wherein a third control oil chamber which causes the internal housing inside the accommodating chamber of the pump housing to move in a direction of decreasing the discharge volume provided, and the third control oil chamber communicates with the temperature-sensitive valve and a portion of the discharge oil can flow thereinto.

The abovementioned problem was resolved by configuring a fourth and a fifth embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a first discharge port, a second inflow port and a second discharge port are formed along an axial direction of the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body has a first communication section and a second communication section in the axial direction, and the first communication section makes the first inflow port and the first discharge port communicate with each other, and the second communication section makes the second inflow port and the second discharge port communicate with each other.

The abovementioned problem was resolved by configuring a sixth and a seventh embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first discharge port, a second discharge port and a third discharge port are formed in order in the cylinder, with the side of the cylinder inflow section being a base point, and a common inflow port capable of communicating with the first discharge port, the second discharge port and the third discharge port is formed in the cylinder, a common communication section is formed in the spool valve body, and the common communication section is capable of making the common inflow port, the first discharge port, the second discharge port and the third discharge port communicate with one another.

The problem was resolved by configuring an eighth and a ninth embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a second inflow port, a first discharge port and a second discharge port are formed in the axial direction in the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body includes a valve interior chamber section, and a valve interior inflow hole and a valve interior outflow hole which make the valve interior chamber section and the exterior of the spool valve body communicate with each other, and an interval between the valve interior inflow hole and the valve interior outflow hole is equal to an interval between the first inflow part and the first discharge port, and between the second inflow port and the second discharge port.

The abovementioned problem was resolved by configuring a tenth and an eleventh embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump wherein an orifice is provided in an inflow section of the second control oil chamber. The abovementioned problem was resolved by configuring a twelfth and a thirteenth embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump wherein an orifice and a drain are provided downstream the third control oil chamber.

The abovementioned problem was resolved by configuring a fourteenth and a fifteenth embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump wherein the internal housing is a rectangular plate-shaped section, and the rotor chamber, which has a circular shape, is formed at an intermediate position of the plate-shape section. The abovementioned problem was resolved by configuring a sixteenth and a seventeenth embodiments of the present invention, respectively, in the main configuration thereof, as a variable-capacity vane pump wherein the internal housing is configured of a ring-shaped section and an operating protrusion section, a recess-shaped operation region is formed in a portion of the accommodating chamber of the pump housing, and the operation protrusion section is arranged inside the recess-shaped operation region.

In the present invention it is possible to make the structure for moving the internal housing of the present invention inexpensive. The temperature-sensitive valve is a valve mechanism in which a non-electronic means, such as thermowax, shape memory alloy or bimetal opens and closes with the oil temperature, and therefore, it is possible to adopt a mechanism based on a non-electronic means, and a device having excellent durability and reliability can be achieved. Moreover, the pressure adjustment valve which discharges oil from the second control oil chamber also functions as a relief valve, and since there is no need to provide a separate relief valve, then the number of components is reduced and the installation space is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic drawing of an oil lubrication circuit according to the present invention which is provided with an internal housing and a pressure adjustment valve according to the first embodiment, FIG. 1B is a schematic drawing showing a state of minimum discharge volume per revolution of the vane rotor and internal housing, and FIG. 1C is a schematic drawing showing a state of maximum discharge volume per revolution of the vane rotor and internal housing;

FIG. 2A is a schematic drawing showing operation at low oil temperature and a uniform rotational speed (750 rpm) in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 2B is an enlarged diagram of part (I) in FIG. 2A, and FIG. 2C is an enlarged diagram of part (II) in FIG. 2A;

FIG. 3A is a schematic drawing showing operation at medium oil temperature and a uniform rotational speed (750 rpm) in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 3B is an enlarged diagram of part (III) in FIG. 3A, and FIG. 3C is an enlarged diagram of part (IV) in FIG. 3A;

FIG. 4A is a schematic drawing showing operation at high oil temperature and a uniform rotational speed (750 rpm) in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 4B is an enlarged diagram of part (V) in FIG. 4A, and FIG. 4C is an enlarged diagram of part (VI) in FIG. 4A;

FIG. 5A is a schematic drawing showing operation at medium oil temperature and a rotational speed of 750 rpm in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 5B is an enlarged diagram of part (VII) in FIG. 5A, and FIG. 5C is an enlarged diagram of part (VIII) in FIG. 5A;

FIG. 6A is a schematic drawing showing operation at medium oil temperature and a rotational speed of 1000 rpm to 1500 rpm in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 6B is an enlarged diagram of part (IX) in FIG. 6A, and FIG. 6C is an enlarged diagram of part (X) in FIG. 6A;

FIG. 7A is a schematic drawing showing operation at medium oil temperature and a rotational speed of 2000 rpm in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 7B is an enlarged diagram of part (XI) in FIG. 7A, and FIG. 7C is an enlarged diagram of part (XII) in FIG. 7A;

FIG. 8A is a schematic drawing showing operation at medium oil temperature and a rotational speed of 2400 rpm in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 8B is an enlarged diagram of part (XIII) in FIG. 8A, and FIG. 8C is an enlarged diagram of part (XIV) in FIG. 8A;

FIG. 9A is a schematic drawing showing operation at medium oil temperature at a rotational speed of 3000 rpm in the present invention which is provided with the internal housing and pressure adjustment valve according to the first embodiment, FIG. 9B is an enlarged diagram of part (XV) in FIG. 9A, and FIG. 9C is an enlarged diagram of part (XVI) in FIG. 9A;

FIG. 10A is a schematic diagram of an oil lubrication circuit provided with the internal housing of the second embodiment of the present invention, and FIG. 10B is a schematic diagram of a state of minimum discharge volume per revolution of the vane rotor and internal housing;

FIG. 11 is a schematic diagram of an oil lubrication circuit according to an embodiment wherein a temperature-sensitive valve is used as a relief valve;

FIG. 12A is a principal schematic diagram of the present invention which is provided with the pressure adjustment valve according to the second embodiment, FIG. 12B is a vertical cross-section schematic diagram showing a first-stage oil discharge state of the pressure adjustment valve, FIG. 12C is a vertical cross-section schematic diagram showing a second-stage oil discharge state of the pressure adjustment valve, and FIG. 12D is a vertical cross-section schematic diagram showing a third-stage oil discharge state of the pressure adjustment valve; and

FIG. 13A is a principal schematic diagram of the present invention which is provided with the pressure adjustment valve according to the third embodiment, FIG. 13B is a vertical cross-section schematic diagram showing a first-stage oil discharge state of the pressure adjustment valve, FIG. 13C is a vertical cross-section schematic diagram showing an oil discharge halted state of the pressure adjustment valve, and FIG. 13D is a vertical cross-section schematic diagram showing a second-stage oil discharge state of the pressure adjustment valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described below with reference to the drawings. The variable-capacity vane pump of the present invention is incorporated into an oil lubrication circuit of a device, such as an engine. The variable-capacity vane pump of the present invention is constituted by a pump housing 1, a vane rotor 2, an internal housing 3, a temperature-sensitive valve 4, a pressure adjustment valve 5 and an elastic member 7 (see FIG. 1A). The temperature-sensitive valve 4, pressure adjustment valve 5 and pump housing 1 may be separate independent parts, or may be incorporated in an integrated fashion into the pump housing 1 to form a single pump unit.

In the pump housing 1, an accommodating chamber 12 is formed in a housing main body section 11. Furthermore, the vane rotor 2 is installed in the accommodating chamber 12 such that the centre of rotation thereof does not move. An intake section 13 where oil is taken in, and a discharge section 14 where oil is discharged, are formed in the pump housing 1.

The vane rotor 2 is configured from a rotor section 21 and vanes 22. A plurality of vane groove sections 21 a, 21 a, . . . are formed in the rotor section 21, and the vanes 22 are inserted into these vane groove sections 21 a, 21 a, . . . (see FIGS. 1B and 1C). The rotor section 21 is assembled such that the centre of rotation thereof does not move with respect to the accommodating chamber 12 of the pump housing 1, and is rotated by the drive force of an engine, or by a motor. With the rotation of the rotor section 21, a portion of the vanes 22 are made to project outside the vane groove sections 21 a by the centrifugal force or oil pressure, or a guide ring (not illustrated), etc., and abuts against the inner circumferential wall of the rotor chamber 32 of the internal housing 3, which is described below.

An internal housing 3 is disposed in the accommodating chamber 12 of the pump housing 1. The internal housing 3 comprises a movable main body section 31 and a rotor chamber 32. The movable main body section 31 is formed in a square shape and a plate shape, and has a rectangular or square external shape (see FIGS. 1B and C). A hollow cylindrical rotor chamber 32 is formed at an intermediate position of the movable main body section 31. The vane rotor 2 is accommodated inside the rotor chamber 32.

There are two embodiments for the internal housing 3. A first embodiment for the internal housing 3 is a linear moving type. The internal housing 3 can move inside the accommodating chamber 12 of the pump housing 1 due to external oil pressure. As stated above, the vane rotor 2 has an immovable position with respect to the accommodating chamber 12 of the pump housing 1, and the internal housing 3 is able to move with respect to the accommodating chamber 12. In other words, the vane rotor 2 and the internal housing 3 move positions relative to each other.

The rotor chamber 32 moves with the movement of the internal housing 3, and due to the movement of the rotor chamber 32, the interval between the centre of rotation Pa of the vane rotor 2 and the centre of diameter Pb of the rotor chamber 32 varies and the oil discharge volume changes. When the interval between the centre of rotation Pa of the vane rotor 2 and the centre of diameter Pb of the rotor chamber 32 becomes smaller, the oil discharge volume from the discharge section 14 becomes smaller (see FIG. 1B), and when the interval between the centre of rotation Pa and the centre of diameter Pb becomes larger, the oil discharge volume becomes larger (see FIG. 1C).

In the description of the present invention, when the internal housing 3 moves from the side of a second control oil chamber S2 to the side of a first control oil chamber S1, the interval between the centre of rotation Pa and the centre of diameter Pb becomes larger, the oil discharge volume increases and, when the interval between the centre of rotation Pa and the centre of diameter Pb is a maximum, the oil discharge volume becomes a maximum. When the internal housing 3 moves from the side of the first control oil chamber S1 to the side of the second control oil chamber S2, the interval between the centre of rotation Pa and the centre of diameter Pb becomes smaller, the oil discharge volume decreases and, when the interval between the centre of rotation Pa and the centre of diameter Pb is a minimum, the oil discharge volume becomes a minimum.

Furthermore, the internal housing 3 moves inside the accommodating chamber 12 of the pump housing 1, and at any position, the internal housing 3 is always able to take in oil from the intake section 13 and to discharge oil from the discharge section 14.

The internal housing 3 moves reciprocally in a linear fashion with respect to the accommodating chamber 12 of the pump housing 1. Gap chambers which expand and contract are formed on both sides of the internal housing 3 in the direction of movement thereof with respect to the accommodating chamber 12, which is formed in a substantially rectangular shape. The gap chambers are two or more chambers into which the accommodating chamber 12 is divided by the internal housing 3. These gap chambers constitute the first control oil chamber S1, the second control oil chamber S2 and a third control oil chamber S3, which are described hereinafter (see FIGS. 1A to 1C).

The first control oil chamber S1 and the third control oil chamber S3 are both formed on the same side of the internal housing 3 (see FIGS. 1A to 1C). The second control oil chamber S2 is formed on the opposite side from the first control oil chamber S1 (see FIGS. 1A to 1C). Furthermore, the first control oil chamber S1 and the third control oil chamber S3 which are on the same side in the direction of movement of the internal housing 3 are divided by a partition section 31 a which is provided in the internal housing 3 (see FIGS. 1B and 1C).

A recess section 12 a into which the partition section 31 a is inserted is formed in the accommodating chamber 12, and the partition section 31 a also moves with the movement of the internal housing 3 inside the accommodating chamber 12, and the partition section 31 a slides inside the recess section 12 a. Consequently, the first control oil chamber S1 and the third control oil chamber S3 are not communicated with each other, due to the partition section 31 a. In other words, the oil that has flowed into the first control oil chamber S1 and the oil that has flowed into the third control oil chamber S3 are at different pressures.

An elastic member 7 is provided in the second control oil chamber S2. The elastic member 7 elastically impels the internal housing 3 towards the first control oil chamber S1. In other words, the elastic member 7 serves to elastically impel the internal housing 3 so as to move in a direction which increases the discharge volume, with respect to the vane rotor 2 (see FIGS. 1B and 1C).

A discharge main flow passage J is provided in the discharge section 14 of the pump housing 1 (see FIG. 1A). The discharge main flow passage J is a flow passage that is incorporated into the device 9 which requires lubricating oil, such as an engine, and circulates the oil from the discharge section 14, towards the intake section 13, via the device 9. An oil pan 17 may also be provided inside the discharge main flow passage J (see FIGS. 1A to 1C). A first control oil passage J1 which branches from the discharge main flow passage J and sends a portion of the discharged oil to the first control oil chamber S1 is provided in the discharge main flow passage J.

The portion of discharge oil that flows in the first control oil passage J1 is called the first branch oil k1. Furthermore, similarly, a third control oil passage J3 which branches from the discharge main flow passage J and sends a portion of the discharge oil to the third control oil chamber S3 is provided in the discharge main flow passage J. The portion of discharge oil that flows in the third control oil passage J3 is called the third branch oil k3.

Furthermore, similarly, a second control oil passage J2 which branches from the discharge main flow passage J of the discharge section 14 and sends a portion of the discharge oil to the second control oil chamber S2 is provided. The portion of discharge oil that flows in the second control oil passage J2 is called the second branch oil k2 (see FIGS. 2A to 4C, etc.). The flow of the first branch oil k1, the second branch oil k2 and the third branch oil k3 is indicated by the arrows in FIGS. 2A to 4C.

The temperature-sensitive valve 4 is a valve which opens and closes in accordance with the temperature of the oil. The temperature-sensitive valve 4 is incorporated into the third control oil passage J3 (see FIG. 1A). The temperature-sensitive valve 4 is configured from a temperature sensing section 41, a piston section 42 and a cylinder section 43. The temperature sensing section 41 is desirably inserted in or adjacent to the discharge main flow passage J, in order to facilitate sensing of the oil temperature. The temperature-sensitive valve 4 closes only when the oil is at high temperature, and therefore the flow passage area gradually changes (decreases) in accordance with change in the oil temperature (gradual increase from a low oil temperature).

To describe the specific configuration of the temperature-sensitive valve 4, a temperature-sensitive valve section 44 is installed in the piston section 42. The temperature-sensitive valve section 44 is formed in a substantially cylindrical inverted cup shape. An inflow hole 44 a which is communicated with the third control oil passage J3 on the upstream side is formed in the top part of the temperature-sensitive valve section 44. Furthermore, an outflow port 43 a which is communicated with the third control oil passage J3 on the downstream side is formed in the cylinder section 43. Oil flows into the cylinder section 43 by passing from the third control oil passage J3 on the upstream side and through the inflow hole 44 a in the temperature-sensitive valve section 44.

By means of the temperature sensing section 41 detecting the oil temperature, the temperature-sensitive valve section 44 moves in the vertical direction inside the cylinder section 43, together with the piston section 42, and thereby opens and closes the outflow port 43 a. By adopting a configuration of this kind, as stated above, the temperature-sensitive valve section 44 operates (descends) in accordance with change in the oil temperature (gradual increase from a low oil temperature), and the flow passage area of the outflow port 43 a gradually changes (decreases).

There are two different embodiments of the specifications of the temperature-sensitive valve 4. Firstly, in a first embodiment of the specifications of the temperature-sensitive valve 4, the temperature-sensitive valve 4 serves to control the movement operation of the internal housing 3 inside the accommodating chamber 12 of the pump housing 1 (see FIGS. 1A to 10B). Furthermore, in a second embodiment of the specifications of the temperature-sensitive valve 4, the temperature-sensitive valve 4 serves as a relief valve for when relieving of the discharge oil becomes necessary due to increase in the pressure as a result of, for instance, change in the temperature of the discharge oil (see FIG. 11).

In this embodiment, oil is discharged into the atmosphere from the outflow port 43 a of the cylinder section 43 of the temperature-sensitive valve 4. In other words, oil is returned to the oil pan 17 or the intake section 13 side of the pump housing 1, from the temperature-sensitive valve 4. More specifically, the outflow port 43 a of the cylinder section 43 and the oil pan 17 are communicated via the third control oil passage J3 on the downstream side (see the third control oil passage J3 which is indicated by the solid line in FIG. 11).

Alternatively, the temperature-sensitive valve 4 and the flow passage near the intake section 13 of the pump housing 1 are communicated via the third control oil passage J3 on the downstream side (see the third control oil passage J3 indicated by the dotted line in FIG. 11). In the second embodiment of the specifications of the temperature-sensitive valve 4, a flow passage to the third control oil chamber S3 is not provided in the pump housing 1, and hence there is no inflow and outflow of oil to and from the third control oil chamber S3 (see FIG. 11).

The pressure adjustment valve 5 discharges the oil in the second control oil chamber S2. There are a plurality of embodiments for the pressure adjustment valve 5. Firstly, a first embodiment for the pressure adjustment valve 5 is described. The pressure adjustment valve 5 is mainly provided with a cylinder 51, a spool valve body 52, an elastic member 53, and the like. A cylinder inflow section 510, a first inflow port 511, a second inflow port 512, a first discharge port 513 and a second discharge port 514 are formed in the cylinder 51. Two narrow-diameter sections are provided in the axial direction of the valve, in the spool valve body 52, of which one is called a first communication section 521 and the other is called a second communication section 522. The first communication section 521 and the second communication section 522 are provided in a serial configuration, separately in the axial direction of the valve (see, FIGS. 1A to 1C, FIGS. 2A to 2C, FIGS. 3A to 3C, etc.).

The pressure adjustment valve 5 is communicated with the second control oil chamber S2 of the pump housing 1 by a discharge oil passage J6. The discharge oil passage J6 is communicated respectively with the first inflow port 511 and the second inflow port 512 of the pressure adjustment valve 5, and more specifically, the flow passage branches into two legs near the first inflow port 511 and the second inflow port 512 (see FIG. 1A).

The elastic member 53 is provided inside the cylinder 51, in such a manner that the spool valve body 52 which is elastically impelled by the elastic member 53 causes the first discharge port 513 and the second discharge port 514 to a closed state. The cylinder inflow section 510 of the cylinder 51 is communicated with the branch passage J5 that branches from the discharge main flow passage J, and is a portion to which the pressure of the oil in the branch passage J5 is applied. As the pressure of the oil present inside the branch passage J5 and the cylinder 51 increases, the spool valve body 52 moves inside the cylinder 51 so as to separate from a base point, which is a position on the side of the cylinder inflow section 510.

The base point of the spool valve body 52 is the position of the front end of the spool valve body 52 when the pump is not operating and the pressure of the oil is not applied. The front end of the spool valve body 52 is the end opposite the cylinder inflow section 510. Due to the movement of the spool valve body 52, the first inflow port 511 and the first discharge port 513, and the second inflow port 512 and the second discharge port 514, are communicated with each other or disconnected from each other, thereby controlling the discharge of oil. The first discharge port 513 and the second discharge port 514 are communicated with the oil pan 17 or the upstream side of the intake section 13 (see FIG. 1A).

The spool valve body 52 moves reciprocally in the axial direction inside the cylinder 51, in accordance with the increase and decrease of the pressure of the oil that flows along the branch passage J5 and into the pressure adjustment valve 5, and the elastic impelling force of the elastic member 53. With the movement of the spool valve body 52 inside the cylinder 51, the first communication section 521 of the spool valve body 52 reaches the position of the first inflow port 511 and the first discharge port 513, whereby the first inflow port 511 and the first discharge port 513 are communicated with each other, and oil inside the second control oil chamber S2 can be discharged via the discharge oil passage J6.

Moreover, the communication between the first inflow port 511 and the first discharge port 513 is disconnected by the movement of the spool valve body 52, and in this case, the second inflow port 512 and the second discharge port 514 are not communicated. When the spool valve body 52 moves further, the second communication section 522 of the spool valve body 52 reaches the position of the second inflow port 512 and the second discharge port 514, whereby the second inflow port 512 and the second discharge port 514 are communicated with each other, and oil inside the second control oil chamber S2 can be discharged via the discharge oil passage J6.

In this case, the communication between the first inflow port 511 and the first discharge port 513 is disconnected. In this way, the pressure of the oil from the branch passage J5 increases due to the increase in the rotational speed, and consequently, from a low rotational speed range to a high rotational speed range, the operation of the pressure adjustment valve 5 stops the discharge of oil by a fully closed state in the initial period of starting up the engine, and thereafter, an oil discharge operation from the first discharge port 513 in a first stage and an oil discharge operation from the second discharge port 514 in a second stage are carried out. At the oil pressure between the oil discharge operation from the first discharge port 513 of the first stage and the oil discharge operation from the second discharge port 514 of the second stage, there is an oil discharge stop range due to a fully-closed state.

In this way, in the first embodiment for the pressure adjustment valve 5, oil discharge inside the second control oil chamber S2 is performed in two stages, and there is a range where the oil discharge is stopped at an oil pressure between the oil discharge of the first stage and the second stage. In other words, even if the rotational speed increases, the internal housing 3 moves towards the second control oil chamber S2, and the discharge pressure can be kept substantially uniform. Furthermore, in the first embodiment for the pressure adjustment valve 5, as described above, a structure is adopted in which the oil discharge operation is configured in two stages, but by increasing the number of communication sections in the spool valve body 52 and also increasing the number of the inflow ports and outflow ports on the side of the cylinder 51, multiple-stage oil discharge having three or more stages is also possible.

Furthermore, as illustrated in FIGS. 12A to 12D, the second embodiment for the pressure adjustment valve 5 is provided with a cylinder 51 and a spool valve body 52, substantially similarly to the first embodiment, a cylinder inflow section 510 is provided in the cylinder 51, the cylinder inflow section 510 and the branch passage J5 that branches from the discharge main flow passage J are communicated with each other, the pressure of the discharge oil in the cylinder 51 is transmitted via the branch passage J5, and the spool valve body 52 moves due to the pressure of the oil.

As illustrated in FIGS. 12A to 12D, a common inflow port 517 is formed in the cylinder 51 at a position separated by a prescribed interval from a position at the base point, in other words, the side of the cylinder inflow section 510. Moreover, a first discharge port 513, second discharge port 514 and third discharge port 516 are formed in the cylinder 51. The first discharge port 513 is formed at a position that is the same as the first inflow port 511 in the axial direction and is different from same in the circumferential direction.

Furthermore, the second discharge port 514 and the third discharge port 516 are formed at mutually different positions to the first discharge port 513 in the axial direction, and at a position further from the first inflow port 511 than the cylinder inflow section 510. In other words, the first discharge port 513 which is closest to the position of the cylinder inflow section 510 in the cylinder 51 is formed, and then the second discharge port 514 and the third discharge port 516 are arranged sequentially in separate fashion in the axial direction.

The common inflow port 517 communicates with the second control oil chamber S2 of the pump housing 1 by a discharge oil passage J6. The spool valve body 52 is configured from a main valve section 52 a, a head section 52 b and a thin shaft section 52 c. The thin shaft section 52 c is communicated with the main valve section 52 a and the head section 52 b in the axial direction. Furthermore, the thin shaft section 52 c is formed with a smaller diameter than the main valve section 52 a and the head section 52 b.

The spool valve body 52 has one depression formed therein by the thin shaft section 52 c between the main valve section 52 a and the head section 52 b, and this depression is called a common communication section 523. Furthermore, the range of the common communication section 523 in the axial direction, in other words, the interval between the main valve section 52 a and the head section 52 b, is of a size that, at the least, enables communication of all of the common inflow port 517, the first discharge port 513, the second discharge port 514 and the third discharge port 516 (see FIGS. 12A to 12D).

The spool valve body 52 is elastically impelled by the elastic member 53 towards to the cylinder inflow section 510, in other words, towards the base point, at all times, and when the pump is not operating, the head section 52 b side of the spool valve body 52 stops at the base point position on the side of the cylinder inflow section 510 (see FIG. 12A). In this state, the common inflow port 517 and the first discharge port 513 are in a completely closed state (fully-closed state) due to the main valve section 52 a of the spool valve body 52. The spool valve body 52 moves reciprocally in the axial direction inside the cylinder 51, in accordance with the increase and decrease of the pressure of the oil in the pressure adjustment valve 5 via the branch passage J5 that branches form the discharge main flow passage J, and the elastic impelling force of the elastic member 53.

With the increase in the pressure of the discharge oil, the spool valve body 52 moves in a direction away from the position of the cylinder inflow section 510, in other words, from the base point position, but at the start of movement, the main valve section 52 a is in a state that closes the common inflow port 517 and the first discharge port 513, so oil does not flow out from the discharge oil passage J6 and therefore no oil is discharged from the second control oil chamber S2.

If the spool valve body 52 continues to move with further increase in the pressure of the oil, then the main valve section 52 a of the spool valve body 52 opens the common inflow port 517 and the first discharge port 513, and the common inflow port 517 and the first discharge port 513 are positioned in the range of the common communication section 523 of the spool valve body 52 and hence the common communication section 523, the common inflow port 517 and the first discharge port 513 are communicated with each other, and first-stage oil discharge of the second control oil chamber S2 is performed (see FIG. 12B).

Next, as the pressure of the discharge oil continues to rise and the spool valve body 52 moves further, the second discharge port 514 opens and becomes positioned within the range of the common communication section 523 of the spool valve body 52, and due to the communication with the common inflow port 517, second-stage oil discharge of the second control oil chamber S2 is performed (see FIG. 12C). In this case, the first discharge port 513 is also positioned inside the common communication section 523, and the oil flows out from the first discharge port 513 and the second discharge port 514.

Moreover, as the movement of the spool valve body 52 continues, the third discharge port 516 opens and becomes positioned within the range of the common communication section 523 of the spool valve body 52, and due to the communication with the common inflow port 517, third-stage oil discharge of the second control oil chamber S2 is performed (see FIG. 12D). In this case, the first discharge port 513 and the second discharge port 514 are also positioned inside the common communication section 523, and the oil flows out from the first discharge port 513, the second discharge port 514 and the third discharge port 516. The first-stage to third-stage oil discharges are performed so that the discharge volume is increased continuously, without stopping the oil discharge between the stages (see FIGS. 12B to 12D).

Furthermore, in the second embodiment for the pressure adjustment valve 5, it is possible to discharge the oil in three stages by means of the first discharge port 513, the second discharge port 514 and the third discharge port 516, but according to requirements it is also possible to adopt a single-stage oil discharge structure based on the first discharge port 513 only, or a multi-stage oil discharge structure having four or more stages by providing four or more discharge ports.

Furthermore, the third embodiment for the pressure adjustment valve 5 is provided with a cylinder 51 and a spool valve body 52, substantially similarly to the first and second embodiments, a cylinder inflow section 510 is provided in the cylinder 51, the cylinder inflow section 510 and the branch passage J5 that branches from the discharge main flow passage J are communicated with each other, the pressure of the discharge oil in the cylinder 51 is transmitted via the branch passage J5, and the spool valve body 52 moves due to the pressure of the oil (see FIGS. 13A to 13D).

The side of the cylinder inflow section 510 is taken as the base point of the spool valve body 52, and the first inflow port 511, the second inflow port 512, the first discharge port 513 and the second discharge port 514 are formed in the cylinder 51, in this order from the base point, in a separated fashion in the axial direction. The spool valve body 52 has a valve interior chamber section 524 constituting an internal gap. The spool valve body 52 also has a valve interior inflow hole 525 and a valve interior outflow hole 526 which communicate with the valve interior chamber section 524 and the exterior of the spool valve body 52. The valve interior inflow hole 525 is positioned further towards the cylinder inflow section 510 than the valve interior outflow hole 526. The spool valve body 52 is elastically impelled towards the cylinder inflow section 510 at all times by the elastic member 53, and when the pump is not operating, the spool valve body 52 stops at the end near the cylinder inflow section 510 (see FIG. 13A).

In the case of this state, the first inflow port 511 and the second inflow port 512 are completely closed by the spool valve body 52. When the spool valve body 52 moves in the opposite direction from the cylinder inflow section 510 inside the cylinder 51, and the valve interior inflow hole 525 arrives at the position of the first inflow port 511, then the valve interior outflow hole 526 arrives at the first discharge port 513, and the first inflow port 511 and the first discharge port 513 become communicated via the valve interior chamber section 524 (see FIG. 13B).

Furthermore, when the spool valve body 52 moves further in the opposite direction from the cylinder inflow section 510, and the valve interior inflow hole 525 arrives at the position of the second inflow port 512, then the valve interior outflow hole 526 arrives at the second discharge port 514, and the second inflow port 512 and the second discharge port 514 become communicated via the valve interior chamber section 524 (see FIG. 13D). In this way, as the spool valve body 52 moves with the increase in the pressure of the discharge oil, firstly, the positions of the valve interior inflow hole 525 and the first inflow port 511, and the positions of the first discharge port 513 and the valve interior outflow hole 526 mutually coincide, and are respectively communicated with each other via the valve interior chamber section 524, and first-stage oil discharge of the oil inside the second control oil chamber S2 is performed.

Moreover, when the spool valve body 52 moves towards the opposite side from the cylinder inflow section 510 due to the increase in the pressure of the discharge oil, the valve interior inflow hole 525 and the second inflow port 512, and the second discharge port 514 and the valve interior outflow hole 526 are communicated with each other via the valve interior chamber section 524, and a second-stage oil discharge of the oil inside the second control oil chamber S2 is performed. In this third embodiment, at an oil pressure between the first-stage oil discharge and the second-stage oil discharge, there is a range where discharge of oil stops.

Next, the operation of the first control oil chamber S1, the second control oil chamber S2, the third control oil chamber S3, the temperature-sensitive valve 4, and the pressure adjustment valve 5 of the variable-capacity vane pump according to the present invention will be described. Firstly, the first branch oil k1 is communicated with the first control oil chamber S1 at all times via the first control oil passage J1 which branches from the discharge main flow passage J, and oil pressure is transmitted to the first control oil chamber S1. In other words, an oil pressure substantially the same as the discharge pressure of the oil flowing from the discharge section 14 to the discharge main flow passage J is applied to the first control oil chamber S1.

Next, in the second control oil chamber S2, the internal housing 3 is elastically impelled at all times in a direction whereby the discharge volume of the discharge oil increases and becomes a maximum, by the elastic member 7 which is installed in the second control oil chamber S2. The second branch oil k2 flows into the second control oil chamber S2 via the second control oil passage J2 which branches from the discharge main flow passage J, and oil pressure is transmitted to the second control oil chamber S2. In other words, when there is no flow of oil to the second control oil chamber S2, an oil pressure substantially the same as the discharge pressure of the oil flowing from the discharge section 14 to the discharge main flow passage J is applied to the second control oil chamber S2.

Moreover, the second control oil chamber S2 is communicated with the pressure adjustment valve 5 by the discharge oil passage J6. The spool valve body 52 of the pressure adjustment valve 5 moves due to the pressure of the oil present in the branch passage J5 that branches from the discharge main flow passage J. The spool valve body 52 performs a moving operation in accordance with the increase and decrease in the discharge pressure from the discharge section 14, and the discharge volume of the oil flowing in from the second control oil passage J2 can be controlled.

Next, the third branch oil k3 flows into the third control oil chamber S3 via the third control oil passage J3 which branches from the discharge main flow passage J, and the temperature-sensitive valve 4. The oil pressure in the third control oil chamber S3 can be changed by adjusting the volume of oil flowing into the third control oil chamber S3.

Next, a second embodiment for the internal housing 3 is described on the basis of FIGS. 10A and 10B. The internal housing 3 of the second embodiment is a swing type. The swing-type internal housing 3 is constituted by a ring-shaped section 35 and an operating protrusion section 36. A rotor chamber 32 is formed on the inner circumferential side of the ring-shaped section 35 and a projection-shaped swinging base section 35 a is formed on the outer circumferential side thereof.

Furthermore, a depression-shaped swing receiving section 12 b is formed in a portion of the inner circumference of the accommodating chamber 12, and the swinging base section 35 a is inserted into the swing receiving section 12 b. Moreover, a recess-shaped operating region 12 c is formed in a suitable portion of the accommodating chamber 12 in the circumferential direction, and the operating protrusion section 36 is arranged swingably therein.

The internal housing 3 performs a swinging motion with respect to the accommodating chamber 12, the centre of the swinging motion being the swinging base section 35 a and the swing receiving section 12 b. The interval between the centre of diameter Pb of the ring-shaped section 35 and the centre of rotation Pa of the vane rotors 2 can be changed by the swinging motion of the internal housing 3. In the recess-shaped operating region 12 c, the internally provided operating protrusion section 36 forms two gap sections, of which one becomes the first control oil chamber S1 and the other becomes the second control oil chamber S2.

Furthermore, the gap formed between the outer circumference of the ring-shaped section 35 of the internal housing 3 and the inner circumference of the accommodating chamber 12, and the swinging base section 35 a and the operating protrusion section 36, forms the third control oil chamber S3. The first control oil passage J1 is communicated with the first control oil chamber S1, the second control oil passage J2 is communicated with the second control oil chamber S2, and the third control oil passage J3 is communicated with the third control oil chamber S3.

The operation of the variable-capacity vane pump according to the second embodiment is equivalent to that of the variable-capacity vane pump according to the first embodiment.

Furthermore, with regard to the first control oil passage J1 and the third control oil passage J3, a configuration may be adopted in which the third control oil passage J3 is communicated with the first control oil chamber S1, and the first control oil passage J1 is communicated with the third control oil chamber S3, and in this case also, similar control can be achieved. However, the first control oil chamber S1 and the third control oil chamber S3 are not communicated with each other.

Furthermore, there is also an embodiment adopting a structure wherein an orifice 15 having a restricted cross-sectional area is provided in the connecting section between the second control oil chamber S2 and the second control oil passage J2. When oil is discharged from the pressure adjustment valve 5, due to the provision of the orifice 15, it is possible to generate a suitable differential between the oil pressure that acts on the second control oil chamber S2 via the second control oil passage J2, and the oil pressure that acts on the first control oil chamber S1 via the first control oil passage J1.

Consequently, the pressure in the second control oil chamber S2 is smaller than the pressure in the first control oil chamber S1, and even if the surface area of the first control oil chamber S1 and the second control oil chamber S2 is the same, it is possible to strengthen the tendency of the internal housing 3 to move in a direction whereby the discharge volume from the discharge section 14 is reduced. In other words, it is possible to more readily obtain a tendency that prevents needless work of the oil, at all times.

There is an embodiment in which a drain orifice 16 having a restricted cross-sectional area is provided on the downstream side of the third control oil chamber S3. The drain orifice 16 serves to make the oil in the third control oil chamber S3 less readily discharged. The drain orifice 16 is used as a restrictor valve which sets the discharge volume from the third control oil chamber S3 situated on the upstream side to a very small volume, and can be used for oil pressure control which enables the oil pressure in the third control oil chamber S3 to be adjusted suitably in accordance with relative size of the volume of oil flowing in the third control oil chamber S3. In the case of the second embodiment implemented according to the specifications for the temperature-sensitive valve 4 (see FIG. 11), since there is no inflow or outflow of oil to or from the third control oil chamber S3 in the pump housing 1, then oil pressure control by the third control oil chamber S3 is not performed.

Next, the action of the present invention will be described in accordance with various situations. Firstly, a situation in which the rotational speed is uniform and the oil temperature increases gradually will be described. Here, the rotational speed range is taken to be a low rotational speed range, and more specifically, the rotational speed of the engine is set to 750 rpm. The low rotational speed range is not limited in particular to the numerical value given above, and this value may be increased or decreased. Furthermore, in the drawings, the flow of oil or transmission of oil pressure in various situations is indicated by the arrows illustrated on the flow paths.

(Low Oil Temperature, Uniform Rotational Speed)

A low oil temperature is set to 40° C. However, the numerical value of the low oil temperature is not limited to this, and this value may be increased or decreased. In a low rotational speed range and at a low oil temperature, as illustrated in FIGS. 2A to 2C, pressure is applied to the first control oil chamber S1 due to the discharge pressure in the discharge section 14, by means of the discharge main flow passage J and the first control oil passage J1. Similarly, oil pressure is transmitted to the second control oil chamber S2 due to the discharge pressure of the discharge section 14, by means of the discharge main flow passage J and the second control oil passage J2. Furthermore, the first control oil chamber S1 and the second control oil chamber S2 have substantially the same oil pressure and pressure receiving surface area, and the oil pressure P1 in the first control oil chamber S1 and the oil pressure P2 in the second control oil chamber S2 result in substantially equal pressures applied to the internal housing 3, and therefore cancel each other out.

Consequently, only the force due to the elastic force of the elastic member 7 remains acting on the internal housing 3, and hence this elastic impelling force of the elastic member 7 acts thereon unaltered. Furthermore, in the second control oil chamber S2, oil is not discharged via the discharge oil passage J6 and the pressure adjustment valve 5 (see FIG. 2C).

The temperature-sensitive valve 4 is fully open at low temperatures (see FIG. 2B). Therefore, in the third control oil chamber S3, the oil flow is large and therefore a high oil pressure is generated, this high oil pressure overcomes the elastic force of the elastic member 7, and the internal housing 3 moves to its maximum limit towards the second control oil chamber S2 (to the left side of the pump housing 1 in FIG. 2A). Consequently, the oil discharge volume from the discharge section 14 becomes a minimum, the discharge volume per revolution is reduced, and fuel consumption can be improved.

(Medium Oil Temperature, Uniform Rotational Speed)

A medium oil temperature is set to 80° C. However, the numerical value of the medium oil temperature is not limited to this, and this value may be increased or decreased. At a medium oil temperature and in a low rotational speed range, as illustrated in FIGS. 3A to 3C, the discharge pressure from the discharge section 14 remains low, because the vane rotor 2 is in the low rotational speed range. Oil pressure is transmitted to the first control oil chamber S1 and the second control oil chamber S2. Furthermore, in the second control oil chamber S2, oil is not discharged via the discharge oil passage J6 and the pressure adjustment valve 5 (see FIG. 3C).

The temperature-sensitive valve 4 becomes half-open (see FIG. 3B), due to the medium oil temperature, and the flow passage area is reduced. Therefore, the volume of oil flowing in the third control oil chamber S3 is reduced, and hence the oil pressure P3 decreases, the combined force of the force due to the oil pressure P1 in the first control oil chamber S1 plus the force due to the oil pressure P3 in the third control oil chamber S3 decreases, and the internal housing 3 moves towards the first control oil chamber S1 (the right side of the pump housing 1 in FIG. 3A). Therefore, the discharge volume per revolution increases. (High Oil Temperature, Uniform Rotational Speed)

A high oil temperature is set to 120° C. However, the numerical value of the high oil temperature is not limited to this, and this value may be increased or decreased. At a high oil temperature and in a low rotational speed range, as illustrated in FIGS. 4A to 4C, the discharge pressure from the discharge section 14 remains low, because the vane rotor 2 is in the low rotational speed range. Oil pressure is transmitted to the first control oil chamber S1 and the second control oil chamber S2. Furthermore, in the second control oil chamber S2, oil is not discharged via the discharge oil passage J6 and the pressure adjustment valve 5 (see FIG. 4C).

The temperature-sensitive valve 4 becomes half-closed (see FIG. 4B), due to the high oil temperature and the flow of oil is stopped. Therefore, the oil pressure P3 in the third control oil chamber S3 becomes substantially equal to the atmospheric pressure, and since the oil pressure P1 and the oil pressure P2 in the first control oil chamber S1 and the second control oil chamber S2 are equal, then only the elastic impelling force of the elastic member 7 acts on the internal housing 3, and the internal housing 3 moves to its maximum limit at a position on the side of the first control oil chamber S1 (the right side of the pump housing 1 in FIG. 4A). Therefore, the discharge volume per revolution from the discharge section 14 becomes a maximum.

Next, a situation where the oil temperature is uniform and the rotational speed changes will be described. Here, the oil temperature is set to 80° C. The oil temperature is not limited in particular to the numerical value given above, and this value may be increased or decreased slightly.

(Uniform Oil Temperature and Rotational Speed of 750 rpm)

The rotational speed of the engine is set to 750 rpm. However, the numerical value is not limited to this, and this value may be increased or decreased slightly. As illustrated in FIGS. 5A to 5C, pressure is transmitted to the first control oil chamber S1 due to the discharge pressure in the discharge section 14, via the discharge main flow passage J and the first control oil passage J1, and oil pressure is also transmitted to the second control oil chamber S2 via the discharge main flow passage J and the second control oil passage J2.

Furthermore, the first control oil chamber S1 and the second control oil chamber S2 have substantially the same oil pressure and pressure receiving surface area, and the oil pressure P1 in the first control oil chamber S1 and the oil pressure P2 in the second control oil chamber S2 result in substantially equal forces applied to the internal housing 3, and therefore cancel each other out. Only the force due to the elastic force of the elastic member 7 remains acting on the internal housing 3, and hence this elastic impelling force of the elastic member 7 acts thereon unaltered. Furthermore, the force of the oil pressure in the branch passage J5 is smaller than the force of the elastic member 53, and the spool valve body 52 cannot be moved to the first-stage opening position, and hence oil is not discharged by the pressure adjustment valve 5 (see FIG. 5C).

The temperature-sensitive valve 4 is in a half-open state at 80° C. (see FIG. 5B). The third branch oil k3 flows into the third control oil chamber S3 via the third control oil passage J3. Therefore, although an oil pressure is generated in the third control oil chamber S3, the oil pressure is low since the temperature-sensitive valve 4 is in a half-open state, and the force due to this oil pressure is slightly greater than the elastic force of the elastic member 7 and hence the internal housing 3 moves slightly towards the second control oil chamber S2 (to the left side of the pump housing 1 in FIG. 5A). Consequently, the oil discharge volume from the discharge section 14 assumes an intermediate state.

(Uniform Oil Temperature and Rotational Speed of 1000 rpm)

The rotational speed is set to 1000 rpm. However, the numerical value is not limited to this, and this value may be increased or decreased slightly. As illustrated in FIGS. 6A to 6C, pressure is transmitted to the first control oil chamber S1 due to the discharge pressure in the discharge section 14, via the discharge main flow passage J and the first control oil passage J1, and oil pressure is also transmitted to the second control oil chamber S2 via the discharge main flow passage J and the second control oil passage J2.

Furthermore, the first control oil chamber S1 and the second control oil chamber S2 have substantially the same oil pressure and pressure receiving surface area, and the oil pressure P1 in the first control oil chamber S1 and the oil pressure P2 in the second control oil chamber S2 result in substantially equal forces applied to the internal housing 3, and therefore cancel each other out. Only the force due to the elastic force of the elastic member 7 remains acting on the internal housing 3, and hence this elastic impelling force of the elastic member 7 acts thereon unaltered. Furthermore, the force of the oil pressure in the branch passage J5 is smaller than the force of the elastic member 53, and the spool valve body 52 cannot be moved to the first-stage opening position, and hence oil is not discharged by the pressure adjustment valve 5 (see FIG. 6C).

The temperature-sensitive valve 4 is in a half-open state (see FIG. 6B). The pressure in the discharge main flow passage J is greater than at 750 rpm, and therefore the flow volume of the third branch oil k3 is greater than at 750 rpm.

Consequently, the pressure in the third control oil chamber S3 is greater than at 750 rpm, and since the force due to this oil pressure is greater than the elastic force of the elastic member 7, then the internal housing 3 moves slightly towards the second control oil chamber S2 (the left side of the pump housing 1 in FIG. 6A). Consequently, the oil discharge volume per revolution from the discharge section 14 is slightly smaller than when the rotational speed is 750 rpm. (Uniform Oil Temperature and Rotational Speed of 1500 rpm)

The rotational speed is set to 1500 rpm. However, the numerical value is not limited to this, and this value may be increased or decreased slightly. The state of the internal housing 3, the temperature-sensitive valve 4 and the pressure adjustment valve 5 when the rotational speed is set to 1500 rpm is substantially the same as when the rotational speed is set to 1000 rpm, as illustrated in FIGS. 6A to 6C. Furthermore, due to the increased rotational speed, the oil discharge volume from the discharge section 14 is increased compared to when the rotational speed to 1000 rpm. In this way, when the rotational speed is set to 1000 rpm to 1500 rpm, the state of the temperature-sensitive valve 4 and the pressure adjustment valve 5 is substantially the same.

(Uniform Oil Temperature and Rotational Speed of 2000 rpm)

The rotational speed is set to 2000 rpm. However, the numerical value is not limited to this, and this value may be increased or decreased slightly. As illustrated in FIGS. 7A to 7C, pressure is transmitted to the first control oil chamber S1 due to the discharge pressure in the discharge section 14, via the discharge main flow passage J and the first control oil passage J1, and oil flows into, and oil pressure is also transmitted to, the second control oil chamber S2 via the discharge main flow passage J and the second control oil passage J2.

Since the rotational speed is 2000 rpm, then the discharge volume from the discharge section 14 increases and the pressure of the oil increases. The force due to the pressure of the oil present in the branch passage J5 increases and exceeds the elastic force of the elastic member 53, and the spool valve body 52 moves. Therefore, the first inflow port 511 and the first discharge port 513 are communicated, and the oil in the second control oil chamber S2 is discharged by the pressure adjustment valve 5 (see FIG. 7C). Therefore, the oil pressure P2 in the second control oil chamber S2 is smaller than the pressure in the first control oil chamber S1.

The temperature-sensitive valve 4 is in a half-open state (see FIG. 7B), the flow volume of the third branch oil k3 is not small, and the third branch oil k3 flows into the third control oil chamber S3 via the third control oil passage J3.

Consequently, the force due to the combined pressure of the oil in the first control oil chamber S1 and the third control oil chamber S3 becomes greater than the combined force of the elastic force of the elastic member 7 and the force due to the pressure of the oil in the second control oil chamber S2, and the internal housing 3 moves towards the second control oil chamber S2 (the left side of the pump housing 1 in FIG. 7A). Consequently, the oil discharge volume per revolution from the discharge section 14 tends to decrease. (Uniform Oil Temperature and Rotational Speed of 2400 rpm)

In FIGS. 8A to 8C, the rotational speed is set to 2400 rpm. However, the numerical value is not limited to this, and this value may be increased or decreased slightly. As illustrated in FIGS. 8A to 8C, the state of the temperature-sensitive valve 4 when the rotational speed is set to 2400 rpm is substantially the same when the rotational speed is set to 2000 rpm (see FIGS. 7A to 7C).

Since the rotational speed is 2400 rpm, then the discharge volume and pressure from the discharge section 14 is further increased compared to when the rotational speed is 2000 rpm, and the pressure of the oil present in the branch passage J5 increases. Consequently, the spool valve body 52 of the pressure adjustment valve 5 moves further to the left, the pressure adjustment valve 5 temporarily becomes fully-closed, and oil is not discharged from the second control oil chamber S2 (see FIG. 8C). The temperature-sensitive valve 4 is in a half-open state (see FIG. 8B). The pressure of the oil from the second control oil passage J2 is transmitted directly to the second control oil chamber S2, and together with the elastic member 7, the internal housing 3 moves towards the first control oil chamber S1 (the right side of the pump housing 1 in FIG. 8A). Consequently, the oil discharge volume from the discharge section 14 tends to increase.

(Uniform Oil Temperature and Rotational Speed of 3000 rpm)

In FIGS. 9A to 9C, the rotational speed is set to 3000 rpm. However, the numerical value is not limited to this, and this value may be increased or decreased slightly. The state of the temperature-sensitive valve 4 when the rotational speed is set to 3000 rpm is substantially the same as when the rotational speed is set to 2400 rpm, as illustrated in FIGS. 9A to 9C.

Since the rotational speed is 3000 rpm, then the discharge volume and pressure from the discharge section 14 is further increased compared to when the rotational speed is 2400 rpm, and the pressure of the oil present in the branch passage J5 increases. Consequently, the spool valve body 52 of the pressure adjustment valve 5 moves further, the second inflow port 512 and the second discharge port 514 are communicated and the pressure adjustment valve 5 becomes fully-open, and oil is discharged from the second control oil chamber S2 (see FIG. 9C). Consequently, even if the rotational speed increases, the increase in oil pressure in the second control oil chamber S2 is almost completely suppressed. With the increase in the rotational speed, the internal housing 3 moves towards the second control oil chamber S2 (the left side of the pump housing 1 in FIG. 9A). Consequently, the oil discharge volume from the discharge section 14 tends to decrease.

As described above, as the rotational speed increases, while the oil temperature is uniform, the discharging of the oil in the second control oil chamber S2 is enabled and stopped, as appropriate, by the pressure adjustment valve 5, and the internal housing 3 is moved towards the second control oil chamber S2 and the side of the first control oil chamber S1. Even if the rotational speed increases in this way, it is still possible to keep the discharge pressure of the oil from the discharge section 14 substantially uniform.

In the present embodiment, the temperature-sensitive valve 4 is arranged in the third control oil passage J3, and the pressure adjustment valve 5 is arranged in the branch passage J5. The length of the third control oil passage J3 to the upstream side of the temperature-sensitive valve 4, and the length of the branch passage J5 to the upstream side of the pressure adjustment valve 5 are both arbitrary and may include a value of zero. This means that a portion of the third control oil passage J3 and the branch passage J5 overlaps with the discharge main flow passage J, and is included in the concept of the present invention.

In the second embodiment, the temperature-sensitive valve has the role of relieving a portion of the discharge oil, and therefore it is possible to control relief over a broad range with respect to the pressure of the discharge oil. In the third embodiment, by providing a temperature-sensitive valve in communication with the third control oil chamber, fine control is possible in accordance with various oil temperatures and oil pressures, and the effect of improving fuel consumption can be raised further. In the fourth and fifth embodiments, it is possible to control the pressure precisely in two stages in the second control oil chamber, and therefore the discharge oil can be adjusted in accordance with various situations. In the sixth and seventh embodiments, it is possible to control the pressure in multiple stages by adjusting the pressure inside the second control oil chamber by a very simple configuration. In the eighth and ninth embodiments, it is possible to control the pressure precisely in two stages, similarly to the fourth and fifth embodiments.

In the tenth and eleventh embodiments, due to the provision of an orifice in the inflow section of the second control oil chamber, it is possible to generate a suitable pressure differential between the oil pressures in the first control oil chamber and the second control oil chamber, when oil is flowing in the second control oil passage, and therefore it is possible to achieve more accurate control using the pressure adjustment valve. In the twelfth and thirteenth embodiments, due to the provision of the orifice and drain to the downstream side of the third control oil chamber, it is possible to set the oil pressure of the third control oil chamber to a suitable value, by adjusting the volume of oil that flows.

In the fourteenth and fifteenth embodiments, the internal housing is configured as a rectangular plate-shaped section, and the rotor chamber having a circular shape is formed at an intermediate position of the plate-shape section, and therefore a very inexpensive configuration can be achieved. In the sixteenth and seventeenth embodiments, the internal housing comprises a ring-shaped section and an operating protrusion section, a recess-shaped operation region is formed in a portion of the accommodating chamber of the pump housing, and the operating protrusion section is arranged inside the recess-shaped operation region, and it is possible to achieve very highly accurate adjustment of the discharge volume. 

1. A variable-capacity vane pump, comprising: a vane rotor configured of a rotor section into which a plurality of vanes are inserted in projectable fashion; an internal housing having a rotor chamber in which the vane rotor is accommodated; a pump housing having an accommodating chamber in which the centre of rotation of the vane rotor is immovable and the internal housing is able to move; a first control oil chamber which moves the internal housing inside the accommodating chamber of the pump housing in a direction of decreasing a discharge volume; a second control oil chamber which moves the internal housing inside the accommodating chamber of the pump housing in a direction of increasing the discharge volume; a pressure adjustment valve which discharges oil inside the second control oil chamber of the pump housing; a temperature-sensitive valve into which a portion of the discharge oil flows; and an elastic member which is provided in the pump housing and which elastically impels the internal housing in a direction of increasing the volume of discharge by the vane rotor, wherein a flow passage area of the temperature-sensitive valve progressively changes as the oil temperature changes, and the pressure adjustment valve changes the discharge volume in accordance with increase in pressure of the discharge oil.
 2. The variable-capacity vane pump according to claim 1, wherein the temperature-sensitive valve has a role of relieving a portion of the discharge oil.
 3. The variable-capacity vane pump according to claim 1, wherein a third control oil chamber which causes the internal housing inside the accommodating chamber of the pump housing to move in a direction of decreasing the discharge volume is provided, and the third control oil chamber communicates with the temperature-sensitive valve and a portion of the discharge oil can flow thereinto.
 4. The variable-capacity vane pump according to claim 1, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a first discharge port, a second inflow port and a second discharge port are formed along an axial direction of the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body has a first communication section and a second communication section in the axial direction, and the first communication section makes the first inflow port and the first discharge port communicate with each other, and the second communication section makes the second inflow port and the second discharge port communicate with each other.
 5. The variable-capacity vane pump according to claim 3, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a first discharge port, a second inflow port and a second discharge port are formed along an axial direction of the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body has a first communication section and a second communication section in the axial direction, and the first communication section makes the first inflow port and the first discharge port communicate with each other, and the second communication section makes the second inflow port and the second discharge port communicate with each other.
 6. The variable-capacity vane pump according to claim 1, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first discharge port, a second discharge port and a third discharge port are formed in order in the cylinder, with a side of the cylinder inflow section being a base point, and a common inflow port capable of communicating with the first discharge port, the second discharge port and the third discharge port is formed in the cylinder, a common communication section is formed in the spool valve body, and the common communication section is capable of making the common inflow port, the first discharge port, the second discharge port and the third discharge port communicate with one another.
 7. The variable-capacity vane pump according to claim 3, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first discharge port, a second discharge port and a third discharge port are formed in order in the cylinder, with a side of the cylinder inflow section being a base point, and a common inflow port capable of communicating with the first discharge port, the second discharge port and the third discharge port is formed in the cylinder, a common communication section is formed in the spool valve body, and the common communication section is capable of making the common inflow port, the first discharge port, the second discharge port and the third discharge port communicate with one another.
 8. The variable-capacity vane pump according to claim 1, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a second inflow port, a first discharge port and a second discharge port are formed in the axial direction in the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body includes a valve interior chamber section, and a valve interior inflow hole and a valve interior outflow hole which make the valve interior chamber section and the exterior of the spool valve body communicate with each other, and an interval between the valve interior inflow hole and the valve interior outflow hole is equal to an interval between the first inflow port and the first discharge port, and between the second inflow port and the second discharge port.
 9. The variable-capacity vane pump according to claim 3, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a second inflow port, a first discharge port and a second discharge port are formed in the axial direction in the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body includes a valve interior chamber section, and a valve interior inflow hole and a valve interior outflow hole which make the valve interior chamber section and the exterior of the spool valve body communicate with each other, and an interval between the valve interior inflow hole and the valve interior outflow hole is equal to an interval between the first inflow port and the first discharge port, and between the second inflow port and the second discharge port.
 10. The variable-capacity vane pump according to claim 1, wherein an orifice is provided in the inflow section of the second control oil chamber.
 11. The variable-capacity vane pump according to claim 3, wherein an orifice is provided in the inflow section of the second control oil chamber.
 12. The variable-capacity vane pump according to claim 1, wherein an orifice and a drain are provided downstream the third control oil chamber.
 13. The variable-capacity vane pump according to claim 3, wherein an orifice and a drain are provided downstream the third control oil chamber.
 14. The variable-capacity vane pump according to claim 1, wherein the internal housing is a rectangular plate-shaped section, and the rotor chamber, which has a circular shape, is formed in an intermediate portion of the plate-shaped section.
 15. The variable-capacity vane pump according to claim 3, wherein the internal housing is a rectangular plate-shaped section, and the rotor chamber, which has a circular shape, is formed in an intermediate portion of the plate-shaped section.
 16. The variable-capacity vane pump according to claim 1, wherein the internal housing is configured of a ring-shaped section and an operating protrusion section, a recess-shaped operation region is formed in a portion of the accommodating chamber of the pump housing, and the operation protrusion section is arranged inside the recess-shaped operation region.
 17. The variable-capacity vane pump according to claim 3, wherein the internal housing is configured of a ring-shaped section and an operating protrusion section, a recess-shaped operation region is formed in a portion of the accommodating chamber of the pump housing, and the operation protrusion section is arranged inside the recess-shaped operation region.
 18. The variable-capacity vane pump according to claim 2, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a first discharge port, a second inflow port and a second discharge port are formed along an axial direction of the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body has a first communication section and a second communication section in the axial direction, and the first communication section makes the first inflow port and the first discharge port communicate with each other, and the second communication section makes the second inflow port and the second discharge port communicate with each other.
 19. The variable-capacity vane pump according to claim 2, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first discharge port, a second discharge port and a third discharge port are formed in order in the cylinder, with a side of the cylinder inflow section being a base point, and a common inflow port capable of communicating with the first discharge port, the second discharge port and the third discharge port is formed in the cylinder, a common communication section is formed in the spool valve body, and the common communication section is capable of making the common inflow port, the first discharge port, the second discharge port and the third discharge port communicate with one another.
 20. The variable-capacity vane pump according to claim 2, wherein the pressure adjustment valve comprises a cylinder and a spool valve body, a cylinder inflow section, into which a portion of the discharge oil flows, is provided in the cylinder, a first inflow port, a second inflow port, a first discharge port and a second discharge port are formed in the axial direction in the cylinder, with a side of the cylinder inflow section being a base point, the spool valve body includes a valve interior chamber section, and a valve interior inflow hole and a valve interior outflow hole which make the valve interior chamber section and the exterior of the spool valve body communicate with each other, and an interval between the valve interior inflow hole and the valve interior outflow hole is equal to an interval between the first inflow port and the first discharge port, and between the second inflow port and the second discharge port.
 21. The variable-capacity vane pump according to claim 2, wherein an orifice is provided in the inflow section of the second control oil chamber.
 22. The variable-capacity vane pump according to claim 2, wherein an orifice and a drain are provided downstream the third control oil chamber.
 23. The variable-capacity vane pump according to claim 2, wherein the internal housing is a rectangular plate-shaped section, and the rotor chamber, which has a circular shape, is formed in an intermediate portion of the plate-shaped section.
 24. The variable-capacity vane pump according to claim 2, wherein the internal housing is configured of a ring-shaped section and an operating protrusion section, a recess-shaped operation region is formed in a portion of the accommodating chamber of the pump housing, and the operation protrusion section is arranged inside the recess-shaped operation region. 